Endocrine Abstracts

There is a known correlation between dyslipidaemia and hypogonadism in diabetes. In non-diabetic men, calculated free testosterone correlates better than total testosterone with the elements of the metabolic syndrome. The aim of this study is to investigate if this was also true in diabetic men.

Methods: This is a retrospective observational study. We analyzed biochemical parameters from 140 sequential male diabetic patients who attended the diabetic erectile dysfunction clinic between 2004 and 2006. Data were collected on testosterone, SHBG, albumin, free and bioavailable testosterone were calculated using the http://www.issam.ch/freetesto.html calculator. These were compared with gonadotrophins, prolactin, lipid profile, glycaemic control and thyroid status. Statistical analysis was by correlation analysis using Bartlett Chi-Squared statistic and Bonferoni correction.

Results: There was a strong correlation between total testosterone and LH levels, however there was no correlation with free testosterone. Calculated free testosterone but not total testosterone correlated with plasma FSH levels (P=0.005 vs 0.148).

There was no significant correlation between the levels of total or free testosterone and HbA₁C, TSH, free T₄, and prolactin.

Testosterone levels showed a significant positive correlation with HDL and a significant negative correlation with total cholesterol and triglycerides. The correlations however, appeared to have better correlation with total rather than calculated free testosterone. Low testosterone strongly correlates with an adverse lipid profile even with the normal range of plasma testosterone in diabetes.

Conclusion: In diabetes, testosterone levels correlate with poor lipid but not glycaemic control. Total testosterone correlates better with both gonadotrophin levels and lipid parameters suggesting calculated free testosterone is less useful in diabetes.